TOMEE-2972 handle removed configuration

This configuration was unused for ages and got removed.
diff --git a/container/openejb-core/src/main/java/org/apache/openejb/cdi/ThreadSingletonServiceImpl.java b/container/openejb-core/src/main/java/org/apache/openejb/cdi/ThreadSingletonServiceImpl.java
index 0b36344..325da56 100644
--- a/container/openejb-core/src/main/java/org/apache/openejb/cdi/ThreadSingletonServiceImpl.java
+++ b/container/openejb-core/src/main/java/org/apache/openejb/cdi/ThreadSingletonServiceImpl.java
@@ -123,7 +123,6 @@
         //from CDI builder
         properties.setProperty(OpenWebBeansConfiguration.INTERCEPTOR_FORCE_NO_CHECKED_EXCEPTIONS, "false");
         properties.setProperty(SecurityService.class.getName(), ManagedSecurityService.class.getName());
-        properties.setProperty(OpenWebBeansConfiguration.CONVERSATION_PERIODIC_DELAY, "1800000");
         properties.setProperty(OpenWebBeansConfiguration.APPLICATION_SUPPORTS_CONVERSATION, "true");
         properties.setProperty(OpenWebBeansConfiguration.IGNORED_INTERFACES, "org.apache.aries.proxy.weaving.WovenProxy");